The Importance of Instrument Calibration
Calibrating an instrument is all about establishing a baseline value, or a reference point within the electronics of the instrument. This is done so that all subsequent readings can relate to a known set value. Unless if the instrument has a reference point then all the readings, or measurements, have very little value.
A good example is a simple pH meter that measures acidity and alkalinity along a scale of 1 to 14 points, the lowest value being more acid - the highest value being more alkaline. The value of 7 is referred to as neutral, as in pure water. Want a more scientific explanation of what exactly pH is….?
Generally, buffers solutions of known values of pH 4, 7 or 10 are used to calibrate a pH meter. The meter is set, or adjusted against a known value during calibration. This allows the pH meter to have reference point so that the readings taken can relate to a set reliable value. If you took a pH reading of pool water without calibrating your instrument, you would have no confidence the value was representative of the true pH.
Moreover, in the environmental consulting industry there several meters that require calibration prior to use; some are photoionization meters (PID) for measuring Volatile Organic Compounds (VOC) in the air, multi-meters to measure groundwater parameters or a water level meter to measure the depth of water in well. Yes; a simple water level meter must be properly calibrated in the form of having reliable tape markings to within 1/100th of an inch.
Imagine if you rented a water level meter that has been incorrectly spliced and the increments are missing a few feet. This means every measurement you take in the field is inaccurate by a few feet. If your project is trying to evaluate the subsurface groundwater gradient direction to determine where a leaking underground storage tank plume is heading and your water tape is off a few feet, then you have a big problem to reconcile. If you never checked your rented tape before it was returned then you may never know why the measurements are false and ultimately your end hydro geologic study could be compromised. This is one example why calibrating an instrument or meter is important.
In fact most environmental consultants establish guidelines for their clients when acquiring groundwater, soil, or air monitoring measurements when conducting operations in the field. These guidelines are often referenced in a document entitled Standard Operating Procedures (SOP). A staple in the industry SOP is to calibrate an instrument in the field prior to use to best establish a true value. This establishes that the conditions in the field are reflected in the calibration as representative of actual field conditions allowing for a more accurate reading.
This is why when renting any piece of equipment to have to assure it has been proper calibrated and has a calibration certificate included. Many regulators require this and may want to see it onsite.
EnviroTech has been in business since 1987 and our qualified staff have been to many manufacturers’ schools to learn the trade of proper calibration. You can be assured when renting equipment from EnviroTech it is properly calibrated and you’ll receive a calibration certificate.
We have video tutorials on calibrating the MiniRAE 3000 Calibration, MultiRAE Lite Calibration, YSI-556 Calibration, and Hanna 991300 Calibration. Let us know if you have other calibration questions, or would like to request a new calibration video for water level meters or other instruments, we will add it to the cue!